I have just installed Ubuntu 12.04 on a dual-stack network (with managed IPv6 configuration). I would like to verify if the DNS resolver options received from DHCP and DHCPv6 servers are correct.

Normally, I would check /etc/resolv.conf, but on Ubuntu it contains only 127.0.0.1. It would be a bit far-fetched to assume that Ubuntu is running a recursive DNS resolver by default, so I think the actual resolver settings are somewhere else.